Preparation and use of a heterogeneous rhodium catalyst for the hydrogenation of a double bond of an α-β-unsaturated carbonyl compound

Abstract

A process for preparing an Rh-based catalytic system heterogenized on an organic or mineral support, characterized in that: a) a rhodium derivative with a valency state>0 is reduced in an ether or aromatic solvent and in the presence of a compound chosen from the group consisting of lipophilic tertiary amines, lipophilic tertiary amides and lipophilic quaternary ammonium salts, and b) the mixture thus obtained is adsorbed onto a suitable organic or mineral support. Use of the abovementioned catalytic system to hydrogenate a C═C double bond of an α,β-unsaturated carbonyl compound.

1. Process for preparing an Rh-based catalytic system heterogenized on an organic or mineral support, characterized in that:
 (a) a rhodium derivative with a valency state >0 is reduced in an ether or aromatic solvent and in the presence of a compound chosen from the group consisting of lipophilic tertiary amines, lipophilic tertiary amides and lipophilic quaternary ammonium salts, resulting in a mixture and 
 (b) the mixture is adsorbed onto a suitable organic or mineral support; 
 wherein the reduction is carried out by hydrogen transfer from a suitable hydrogen donor at a pressure of between 1 and 5 atm (14.69–73.45 psi) and at a temperature of between 15 and 40° C. 
 
     
     
       2. Process according to  claim 1 , wherein the rhodium derivative is a halide. 
     
     
       3. Process according to  claim 2 , wherein the ether or aromatic solvent is chosen from the group consisting of tetrahydrofuran, 1,2-dimethoxyethane, diglyme, toluene, mesitylene, isopropylbenzene and cumene. 
     
     
       4. Process according to  claim 3 , wherein the lipophilic tertiary amine is an amine of formula NTT′T″, in which T, T′ and T″, which may be identical or different, are a linear or branched alkyl containing from 4 to 20 carbon atoms, a cycloalkyl containing from 5 to 10 carbon atoms or an alkylphenyl in which the alkyl contains from 1 to 20 carbon atoms. 
     
     
       5. Process according to  claim 3 , wherein the lipophilic tertiary amide is an amide X—CO—NX′X″, in which X′ and X″, which may be identical or different, are a linear or branched alkyl containing from 4 to 20 carbon atoms, a cycloalkyl containing from 5 to 10 carbon atoms or an alkylphenyl in which the alkyl contains from 1 to 20 carbon atoms. 
     
     
       6. Process according to  claim 3 , wherein the lipophilic quaternary ammonium salt is a quaternary salt of formula [NY 1 Y2Y 3 Y 4 ] +  Z −  in which Y 1 , Y 2 , Y 3  and Y 4 , which may be identical or different, are a linear or branched alkyl containing from 1 to 20 carbon atoms, a cycloalkyl containing from 5 to 10 carbon atoms or an alkylphenyl in which the alkyl contains from 1 to 20 carbon atoms, on condition that the total number of carbon atoms in the quaternary salt is at least 14; Z −  is Br − , Cl − , OH −  or HSO 4 . 
     
     
       7. Process according to  claim 4 , wherein the tertiary amine trioctylamine or hexadecylamine. 
     
     
       8. Process according to  claim 4 , wherein the (amine or amide or ammonium salt)/rhodium salt molar ratio is between 2 and 5. 
     
     
       9. Process according to  claim 8 , wherein the mineral support is chosen from the group consisting of: Al 2 O 3 , pumice, hydrotalcite, C, SiO 2  zeolites, TiO 2  and ZrO 2 . 
     
     
       10. Process according to  claim 9 , wherein the mineral support is a γ alumina. 
     
     
       11. Process according to  claim 10 , wherein the catalytic system is prepared in a single phase. 
     
     
       12. Process according to  claim 1 , wherein the ether or aromatic solvent is chosen from the group consisting of tetrahydrofuran, 1,2-dimethoxyethane, diglyme, toluene, mesitylene, isopropylbenzene and cumene. 
     
     
       13. Process according to  claim 1 , wherein the (amine or amide or ammonium salt)/rhodium salt molar ratio is between 2 and 5. 
     
     
       14. Process according to  claim 1 , wherein the mineral support is chosen from the group comprising: Al 2 O 3 , pumice, hydrotalcite, C, SiO 2  zeolites, TiO 2 , and ZrO 2 . 
     
     
       15. Process according to Claim  1 , wherein the catalytic system is prepared in a single phase. 
     
     
       16. Process according to  claim 1 , wherein the reduction is carried out with hydrogen. 
     
     
       17. Process for hydrogenating the C═C double bond in α,β-unsaturated carbonyl compounds of general formula (I) according to the following reaction scheme: 
       
         
           
           
               
               
           
         
       
       in which
 A is hydrogen, linear or branched alkyl containing from 1 to 8 carbon atoms, cycloalkyl containing from 5 to 10 carbon atoms, COOR or CONRR′ in which R and R′, which may be identical or different, are hydrogen, linear or branched alkyl containing from 1 to 8 carbon atoms or cycloalkyl containing from 5 to 10 carbon atoms, or A has the meanings given below for Ar 
 n is 0, 1 or 2; 
 Ar is phenyl, naphthyl or a 5- to 7-membered heteroaryl containing 1 or 2 hetero atoms chosen from O, N and S, in which the said phenyl, naphthyl and heteroaryl may be substituted with one or more C 1 –C 2  alkyl groups or one or more OH, OR, halogen, COOR or CONRR′ groups, in which R and R′, which may be identical or different, are hydrogen, benzyl, linear or branched alkyl containing from 1 to 8 carbon atoms or cycloalkyl containing from 5 to 10 carbon atoms, wherein 
 the hydrogenation is carried out by contacting α,β-unsaturated carbonyl compounds with an Rh-based catalytic system prepared according to  claim 4 . 
 
     
     
       18. Process according to  claim 17 , wherein the hydrogenation is carried out at a temperature of between 0° and 100° C. 
     
     
       19. Process according to  claim 18 , wherein the hydrogenation is carried out at a temperature of between 20° and 80° C. 
     
     
       20. Process according to  claim 19 , wherein the hydrogenation is carried out at a pressure of between 1 (14.69 psi) and 20 atm (293.8 psi). 
     
     
       21. Process according to  claim 20 , wherein the hydrogenation is carried out in the presence of a solvent of medium or low polarity chosen from the group comprising linear or branched aliphatic hydrocarbons containing from 6 to 12 carbon atoms; cyclic hydrocarbons containing from 6 to 10 carbon atoms; aromatic hydrocarbons: aliphatic esters; aliphatic ethers and chlorinated aliphatic solvents. 
     
     
       22. Process according to  claim 21 , wherein the solvent of medium or low polarity is chosen from the group comprising toluene, xylene, mesitylene, isopropylbenzene, cumene, ethyl acetate, isopropyl acetate, butyl acetate, tetrahydrofuran and mesitylene chloride. 
     
     
       23. Process according to  claim 22 , wherein in the compound of general formula (I), Ar is (6′-methoxy-2′-naphthyl) or (2′,3′-dimethoxyphenyl), n=0 and A is methyl, COOH, COOO(C 1 –C 4 )alkyl or COO-benzyl. 
     
     
       24. Process according to  claim 17 , wherein the hydrogenation is carried out at a pressure of between 1 (14.69 psi) and 20 aim (293.8 psi). 
     
     
       25. Process according to  claim 17 , wherein the hydrogenation is carried out in the presence of a solvent of medium or low polarity chosen from the group comprising linear or branched aliphatic hydrocarbons containing from 6 to 12 carbon atoms; cyclic hydrocarbons containing from to 10 carbon atoms; aromatic hydrocarbons: aliphatic esters; aliphatic ethers and chlorinated aliphatic solvents. 
     
     
       26. Process according to  claim 17 , characterized that, wherein in the compound of general formula (I), Ar is (6′-methoxy-2′-naphthyl) or (2′,3′-dimethoxyphenyl), n=0 and A is methyl, COOH, COOO(C1–C4)alkyl or COO-benzyl.